Effect of Asp-97-->Glu substitution on the pH dependence of catalysis by inorganic pyrophosphatase of Escherichia coli.
Substitution of Glu for the evolutionarily conserved Asp-97 in the active site of Escherichia coli inorganic pyrophosphatase increases the apparent pKa of the essential acidic group controlling the catalytic constant for pyrophosphate hydrolysis. In combination with previously reported data, this fact suggests that activity decreases in alkaline medium because of decreased rate of the release of the first molecule of the product phosphate from the active site.
Fabrichniy
I P
IP
Belozersky Institute of Physico-Chemical Biology and School of Chemistry, Lomonosov Moscow State University, Russia.
Lahti
R
R
Baykov
A A
AA
D019943:Amino Acid Substitution; D001224:Aspartic Acid / Q000378:metabolism*; D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology*; D018698:Glutamic Acid / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D043564:Inorganic Pyrophosphatase; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism*
D001224:Aspartic Acid; D018698:Glutamic Acid; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase